[gcc(refs/users/guojiufu/heads/guojiufu-branch)] [Ada] Fix handling of 'Enum_Rep and renamings

[gcc(refs/users/guojiufu/heads/guojiufu-branch)] [Ada] Fix handling of 'Enum_Rep and renamings

[Jiu Fu Guo]

https://gcc.gnu.org/g:8eda13a49e566270f04323dbec11b2e86d3ddccc

commit 8eda13a49e566270f04323dbec11b2e86d3ddccc
Author: Arnaud Charlet <charlet@adacore.com>
Date:   Fri Feb 14 11:50:12 2020 -0500

    [Ada] Fix handling of 'Enum_Rep and renamings
    
    2020-06-08  Arnaud Charlet  <charlet@adacore.com>
    
    gcc/ada/
    
            * sem_eval.adb (Eval_Type_Conversion): Fix handling of
            enumeration to integer conversions.
            * exp_attr.adb (Expand_N_Attribute_Reference
            [Attribute_Enum_Rep]): Remove special casing for first-level
            renaming, best left to the general folding mechanism via
            Eval_Type_Conversion.

Diff:
---
 gcc/ada/exp_attr.adb | 15 ---------------
 gcc/ada/sem_eval.adb |  8 ++++++--
 2 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/gcc/ada/exp_attr.adb b/gcc/ada/exp_attr.adb
index aac5972c6f9..c282e767ad6 100644
--- a/gcc/ada/exp_attr.adb
+++ b/gcc/ada/exp_attr.adb
@@ -3168,21 +3168,6 @@ package body Exp_Attr is
             Rewrite (N,
               Make_Integer_Literal (Loc, Enumeration_Rep (Entity (Expr))));
 
-         --  If this is a renaming of a literal, recover the representation
-         --  of the original. If it renames an expression there is nothing to
-         --  fold.
-
-         elsif Nkind (Expr) in N_Has_Entity
-           and then Ekind (Entity (Expr)) = E_Constant
-           and then Present (Renamed_Object (Entity (Expr)))
-           and then Is_Entity_Name (Renamed_Object (Entity (Expr)))
-           and then Ekind (Entity (Renamed_Object (Entity (Expr)))) =
-                      E_Enumeration_Literal
-         then
-            Rewrite (N,
-              Make_Integer_Literal (Loc,
-                Enumeration_Rep (Entity (Renamed_Object (Entity (Expr))))));
-
          --  If not constant-folded above, Enum_Type'Enum_Rep (X) or
          --  X'Enum_Rep expands to
 
diff --git a/gcc/ada/sem_eval.adb b/gcc/ada/sem_eval.adb
index 2fab4bb9a6f..96d6b9315ff 100644
--- a/gcc/ada/sem_eval.adb
+++ b/gcc/ada/sem_eval.adb
@@ -4031,8 +4031,13 @@ package body Sem_Eval is
 
             --  Real to integer conversion
 
-            else
+            elsif To_Be_Treated_As_Real (Source_Type) then
                Result := UR_To_Uint (Expr_Value_R (Operand));
+
+            --  Enumeration to integer conversion, aka 'Enum_Rep
+
+            else
+               Result := Expr_Rep_Value (Operand);
             end if;
 
             --  If fixed-point type (Conversion_OK must be set), then the
@@ -4076,7 +4081,6 @@ package body Sem_Eval is
       if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then
          Out_Of_Range (N);
       end if;
-
    end Eval_Type_Conversion;
 
    -------------------